Conductor for the transmission of electrical energy and method of producing the same



Nov. 13, 1928. 1591,029

F. BANDUR CONDUCTOR FOR THE NSMISSION OF ELECTRICAL ENERGY AND METHOD OF PRODUCING THE SAME Filed April 22, 1924 flwenior Adqlp/z FBandur Patented Nov. 13, 19 28.

UNITED STATES PATIENT OFFICE- v ADOLPH FRANCISBANDUR, O1 IBERWYN, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., CORPORATION. OF NEW YORK.

CONDUCTOR FOR THE TRANSMISSION OF ELECTRICAL ENERGY AND METIOD OF PRO- DUCING THE SAME.

Application filed Apr-1122, 1924. Serial No. 708,128.

This invention relates to conductors for the transmission of electrical energy and methods of producing the same, and more particularly to composite signalling conductors having an 5 external layer of material of high permeability for the purpose of increasmg the mductance of the conductor, the electrical characteristics of the material being determined to some extent by heat treatment. One manner of increasing the inductance of a conductor employed for the transmission of alternating current is to wrap the conductor spirally with a layer of wire or tape of 1nagnetic material. This method is known H1 the art as continuous inductive loading as distinguished from lump loading by means of coils distributed alon the conductor. Until recently iron has een considered to be the only material available for continuous loading. .It has been discovered, however,

that a more suitable material may be produced in the form of an alloy of nickel and 1r'on..v

When these two metals are in proper proportions and the alloy is given proper heat treat ment, a material having very high permes ability at low magnetizing forces is obtained.

For a full disclosure of the metallurgical and electrical characteristics of this alloy and its heattreatment, reference is made to the patents of Gustave W. Elmen, 1,586,884,

lssued June 1, 1926 Oliver E. Buckley, 1,586,-

874, issued June 1, 1926, and Gustave W. Elf men, 1,586,887, issued June 1, 1926.

One method of applying the alloy loading 5 material above described to a composite signallin conductoris that described in Patent 1,537 ,5 5, issued May 12, 1925, in WhlCh the loading material is applied in theform of tape wrap (1 around the conductor and sub- 40 jected to t e requisite heat treatment while wrapped thereon. I

It has been found that when this alloy loading material is subjected to stresses or strains thatthe permeability thereof is materially lowered and that in some cases these deleterious stresses or strains occur during the heat treatment of the loading material and are due-to the construction of the composite conductor.

An object of this invention isto provide a com osite electrical conductor so treated that w en it has been wrapped with a maguring a plurality of samples of t vide a method of treatment for the composite conductor prior to the application of the magnetic material thereto.

In accordance with the invention the composite conductor is coated with a non-combustible lubricating material which will permit relative movement between the composite conductor and the magnetic loading tape,

durin the'heat treatment of the latter without subjecting the loading tape to deleterious stresses or strains.

Other objects and advantages of'the invention will appear from the following detailed description and will'be particularl pointed out in the appended claims.

In the accompanying drawings, Fig. 1 is a fragmentary side elevation of a composite conductor made in accordance with the invention, part of the alloy loading tape being cut away to moreclearly show the composite conductor and the lubricating material applied thereto, and a 1 Fig.2 is a vertical sectional view of Fig. 1. In carrying out the invention a composite conductor is produced consisting of a central conductor 5, around which a ralitv of copper segmental stri s 6, preferab y six in number, are stran ed so that they lie flat thereagainst. The composite The central copper conductor 5 and the.

segmental strips 6 have a higher coefiioient of elongation than the alloy tape 8. .Meas e composite pluconductor thus produced is then coated with 1 conductor and the alloy tape, the former has been found to have a coefficient of elongation from 11 to 53 per cent. higher than that of the alloy tape. Due to this difierence, unless precautions are taken to prevent it, the natural tendency of the composite con-v ductor to expand more rapidly than the alloy tape will cause the latter to be subjected to deleterious stresses and strains during the heat treatment thereof. The difiiculty of obviating these stresses and strains is increased, since during the heat treatment of the loaded conductor it is raised from room temperature to 1530 F. during approximately 47 seconds time.

Due to the fact that the strips 6 are relatively flat, upon being stranded around the central conductor 5, they do not present a true cylindrical surface because the edges of the strips do not lie flat against the central conductor, but present spiral ridges. During the heat treatment the alloy tape 8 and copper strips 6 tend to move relatively to each other due to their different coefiicients of elongation, and unless some means is provided to prevent it, the ridges formed by the strips 6 cause a sticking between the said strips and the alloy tape 8, subjecting the latter to deleterious stresses and strains, both during the heating and cooling thereof. However, when powdered mica is coated over the ridges formed by the strips 6, a noncombustible lubricant is provided which prevents sticking between the strips 6 and alloy tape 8 and permits relative movement between them during the heating and cooling thereof, incident to the heat treatment of the alloy tape. Where the strips 6 and alloy tape 8 are free to move relatively to each other during the heat treatment, the alloy tape 8 is not subjected to deleterious stresses or strains at a time when such stresses or strains have a very great eflect upon its electrical characteristics.

What is claimed is:

1. A loaded signalling conductor comprising a central conductor, a coating of material thereon which will act as a separator and which will not be consumed on being subjected to heat treatment, and a ma netic loading material wrapped around sai central conductor, said loading material requiring heat treatment to give it a desired electrical characteristic.

2. A loaded signalling conductor comprising a central conductor, a coating of powdered mica, and a magnetic loading material wrapped around said central conductor, said loading material requiring heat treatment to give it a desired electrical characteristic.

3. A loaded signalling conductor comprising a composite metallic strand consisting of a metallic wire wra ped with metallic strip, a coating of materia on said composite strand which will act as a separator and which will not be consumed on being subjected to heat treatment, and a magnetic loading material Wrapped around said composite strand, said loading material requiring heat treatment to give it a desired electrical characteristic.

4. A loaded signalling conductor comprising a composite strand consisting of a metallic wire wrapped with relatively fiat metallic strip, a coating of mica on said metallic strip, and a magnetic loading material wrapped around said composite strand, said loadmg material requiring heat treatment to give it a desired electrical characteristic.

5. The method of loading a signalling conductor with magnetic material requiring heat treatment to give it a desired electrical characteristic, consisting in coating the central conductor with a separating material, wrapping the loading material around the said coated conductor, subjecting the thus assembled conductor to heat treatment, and preventing the destruction of the separating material by the heat treatment.

6. The method of loading a signalling conductor with magnetic material requiring heat treatment to give it a desired electrical characteristic, consisting in wrapping a metallic wire with relatively flat metallic strip, coating the said strip with a separating material, wrapping the loading material around the coated composite strand, annealing the conductor, and maintaining the separating material intact during the annealing process.

7. The method of loading a signalling conductor with magnetic material which requires heat treatmentto giveit a desired electrical characteristic, which consists in stranding a plurality of relatively flat copper strips around a copper wire, coatin the outer surface of the stri s with pow ered mica, and then wrapping t e magnetic loading material 1n the form of relatively flat metallic-tape around the coated composite strand, annealmg the conductor, and retaining the mica in its original form.

8. The method of preventing a decrease in the permeability of a magnetic material app l1ed to an electrical conductor, which consists in applying a layer of separating material to said conductor prior to wrappin the magnetic material thereon, annealing said magnetic material, and retaining the separator between the conductor and the magnetic material by means of a separating material due to its not being consumed.

9. A loaded signaling conductor comprismg a central conductor, a magnetic loading material wrapped aroundsaid central conductor, said loading material requiring heat treatment to give it a desired electrical characteristic, and a' separator located between said central conductor and said magnetic loading material, which will not be consumed upon bein subjected to the hi h temperalture incident t e heat treating o the magnetic loading material.

10. The method of preventing a decrease 5 in permeability of a magnetic material applied to an. electrical conductor, which consists in applying a non-combustible separator to the conductor prior to application of the magnetic material thereto, annealing said magnetic material, and retaining the separator intact during the annealing process;

In'witness whereof, I hereunto subscribe my name this 11th day of April, A. D. 1924.

ADOLPH FRANCIS BANDUR. 

